Raphael josia



NITE TA'IES ATENI @rrrcs,

RAPHAEL JOSIA, OF FLORENCE, ITALY, ASSIGNOR TO WILLIAM REY AND C. DEVARIGNY, BOTH OF PARIS, FRANCE.

COMPOSITION FOR TREATING SULPHATES F LIME FOR THE MANUFACTURE OFARTIFICIAL MARBLE.

SPECIFICATION formingpart of Letters Patent No. 265,509, dated October3, 1882.

I Application filed August 9, 1882. (N0 specimens.)

To all whom it may concern Be it known that I, RAPHAEL JOSIA, ofFlorence, Kingdom of Italy, have invented or discovered a new and usefulImprovementin Compositions for Treating Sulphates of L me for theManufacture ofArtificial Marble; and I do hereby declare the followingto be a full, clear, concise, and exact description thereof.

In an application for Letters Patent of the United States filed March 2,1882, I have described and made claim to an improved process of treatingor preparing gypsum (calcic sulphate or sulphate of lime) in the makingof articles of a material which I have termed certaldite withoutpulverization of the gypsum. In said application I described brieflycertain of the compounds or compositions which I employ to producecertain effects and the manner of using them, but stated that separateappli- '20 cations would be made for patents for such compositions.

The present application relates to one of the compositions so referredto, and it is designed for use in the process herein described in themaking of light-green certaldite.

In carrying out the process referred to a suitable piece of gypsum(calcic sulphate) is first formed into the desired shape, orapproximately such, by the use of suitable well-known tools. The gypsumemployed may be the ordinary native gypsum of commerce, though I preferthat which is comparatively pure or free from other matters of differentcomposition. Such gypsum is usually obtained hydrated, or

5 containing a certain percentage of water in its composition; and thesecond step in the operation has reference to depriving the gypsum undertreatment of a considerable part or the whole of such water. This isdone by subjecting it to the action of a gradually-increasing heat,varying by preference with the size and quality of the material from 260to 300 Fahrenheit, for about twelve hours, or until the desired partialor complete dehydration 5 is obtained. The length of time as well as thedegree of heat required to effect this result will vary somewhat withthe size, character, and purity ofthe gypsum employed ;Y but thetemperature should not exceed 500 Fahro enheit, and both it and the timeof exposure should be regulated and limited with reference to securinguniformity of treatment throughout the whole mass or body. Thisoperation may be known to be complete when a fracture of a test blockpresents a uniform white color. Any suitable drying or baking apparatusmay be employed for this purpose, many such being known in kindredbranches of the arts; but it should be of such construction that thematerial under treatment shall not be brought into direct contact withthe fire. When the desired dehydration has been effected the furnace isallowed to cool gradually, in order that the material under treatmentmay be cooled gradually;

or the material may be removed with due care to prevent breaking andexposure to moisture, and allowed to cool outside the furnace graduallyuntil it is reduced in temperature sufficiently to permit handling withsafety in its subsequent treatment, which is designed to 0 impart to itthe desired color or tint and a high degree ofinsolubility and hardnessthroughout its mass. This step involves the use of the composition whichforms the subject-matter of invention in the present applicatim. Thiscomposition is formed of the following elements: water, by weight, twohundred parts; alum, by weight, three to four parts; logwood, by weight,two to three parts; sulphate ofindigo, by weight, one to two parts.These ingredients, being mixed in about the proportions named, form asolution which is used as a bath, and to this end a suitable quantity ofit is placed in a vessel of proper shape to receive the article to betreated, which is dipped or immersed in the bath and subjected to itsaction until the article has acquired the desired degree of hardness andof color. The length of time required to effect this result will dependsomewhat on'the'strength of theingre- 9o dients composing the bath orsolution, the porosity and nature or physical and chemical condition ofthe article; but usually twelve hours (more or less) will sufljce,though to secure uniformity of treatment and of result 5 through thewhole body or mass of the article I prefer repeated dippin gs-two,three,or more say two or three seconds at first, and increasinggradually to one, two, three, or more minutes, more or less, with dryingintervals of too like increasing length between clippings, for

half or three'quarters of an hour or so, after which the article mayremain in the bath for twelve hours or so.

Vhile I do not limit my invention by any particular theoryot' chemicalor physical reactions involved in the use of this bath as abovedescribed, I believe, with my present knowledge, that the alum held insolution, by taking the place of the molecules of water displaced by theprevious dehydrating operation, acts chemically or physically upon thecalcic sulphate and renders it more compact, harder, and less soluble,and that it also has a like indurating action upon the impurities ormatters of other composition, (carbonates, &c.,) which are usuallycontained in greater or less quantities in native gypsums. lhe logwoodand sulphate of indigo of the bath are employed as coloring agents, andby varying the propor tions of these elements as above indicated variouslighter shades of green may be obtained, which appear not alone upon thesurface of the article treated, but ditfused throughout its mass withlines, veins, or markings of darker shades of color running through itirregularly, which are due probably toimpurities presentin the calcicsulphate. A highlyornamental and beautifully variegated green color isthus se cured, as well as such a degree of hardness,

density, and insolubility as renders the article.

(certaldite) an excellent substitute formarbles, ornamental stones.tiles, and other materials of kindred nature in the various uses towhich they are applied in the arts.

When the article has been treated in the bath as above described it isremoved and dried by exposure to the sun or to an equivalentfurnace-heat for one or two hours, or by ordinary atmospheric exposuret'ortwo or three days, when it is ready for polishing and such othermanipulation as may best fit it forits intended use, which may be doneby any of the methods practiced in kindred arts.

No claim is made herein to the process set forth, as that, with variousmodificatiousof the same, as circumstances may require, forms the tionof the bath upon the interior substance of the article; or if thesolution be very weak too much time is required, and even then a properdegree of hardness, density, and insoL ability is not secured; also, bythe conjoint action of all the elements of the bath much better resultsare secured, especially upon native gypsums, than by a solution formedof a part of the elements. For these reasons I prefer to employ all theelements of the composition in substantially the proportions named; butsuch limits, though affording the best results, may be varied orexceeded somewhat and still obtain favorable results under skillfulmanipulation, and all such modifications employing the elementssubstantially as herein described in about the proportions set forth Iconsider as coming within myinvention and claim.

I claim as my invention- The composition herein described for treatingdehydrated gypsum, consisting substantially of the following elements:water, alum, logwood, and sulphate of indigo, in about the proportionsset forth.

In testimony whereof I have hereunto set my hand.

RAPHAEL JOSI A.

\Vitnesses:

GUIDO PANTALIONY, 1-1.. ll. \Vrrrramnsnv.

Neither do I limit my present in-

